Growing Your Garden: The benefits of raised bed gardening

While it still might be too early to get out in the garden, it is definitely not too early to consider the benefits of raised bed gardens.

Raised bed gardens typically stand about 30 centimetres above the ground (although they can be double that amount) and can be free-form (with the soil heaped up) or framed with planks of wood or edged with stone or concrete blocks.

The simplest designs are boxes made of wood (or corrugated metal) that hold the planting medium above the level of the soil. More permanent designs include a low wall of tumbled stone or concrete blocks, basically you can use whatever you have on hand.

Raised bed gardens can be problem solvers by creating better gardening conditions where the native soil is less than ideal. For example, on heavy clay soils, a raised bed will drain more quickly; on thin, sandy soils, the raised bed will be better able to retain moisture. A raised garden can be tilled from the footpath, meaning the soil does not get compacted with foot traffic, and, when well designed, it can be easier to maintain, with less bending and stretching required.

In my Niagara garden, we have installed several raised beds that make gardening on heavy clay soil more manageable. To make the most of a south-facing wall, large tree bins are used to create a handsome raised garden, edged in cedar, for gourmet tomatoes.

In the circle garden, a central raised bed surrounded by a walkway of concrete pavers creates a sheltered microclimate that warms much earlier in the spring than the main garden, and stays warm and dry later into the autumn. Predominantly an herb garden, its warm, well-drained soil welcomes early spring daffodils, tulips and alliums while perennial sage, tarragon, lavender and thyme plants bulk up in the spring. By early summer, annual herbs such as basil, parsley and rosemary have settled in along with seed grown marigolds and miniature dahlias.

Maintenance is simple, no matter the weather, because the beds warm early in the season and the pathways are always dry. It is easy to reach across the bed with a cultivator when necessary. When initially planted, this bed was filled with triple mix, and seasonal amendments of well-aged manure and/or compost keep the planting bed well fed and healthy.

Raised garden beds are ideal for today’s smaller lots. Rather than dig up a plot for a veggie garden, a tidy row of raised beds, with a mulched footpath and possibly an arbour, create a practical and attractive way to expand your garden’s footprint.

So where to start? First, consider the space you have available. If you are new to gardening, start small and build extra raised beds when and if they are required. You will be surprised how much produce can be grown in a small raised bed. Most vegetables, fruits and many flowers prefer a sunny location with at least six to eight hours of sunlight per day. The exception is lettuce and Swiss chard, which accept less sun. A nearby water source is also important, you’ll want convenient access to the garden hose or a rain barrel.

While we are on the subject of convenience, raised beds for herbs, tomatoes, beans or lettuce should be handy to the kitchen door or patio if possible. In my garden, the raised herb garden is just steps from the kitchen door, making it easy to slip out and snip a few fresh herbs for the table. Positioning the raised garden in close proximity to the house also makes it more convenient to monitor the beds for pests, weeds or to offer a quick drink of water if something is languishing on a hot day.

When planning a raised bed, the sod does not have to be removed before filling the form with your planting mixture. You can put down a thick layer of cardboard or newspapers (to kill the grass and act as a weed barrier) and then simply fill the form with your preferred soil mix.

For the more ambitious, you can also create your own soil, by layering cardboard, small twigs (from pruning) cut into small pieces, and topped with layers of soil and green material (leaves). This lasagna-style mix is left to age over the winter and will be ready to plant the following spring.

To further enhance a raised garden design, a small arbour, trellis or obelisk adds height and strength, and will also increase the amount of produce you will be able to grow in a small space. Crops such as cucumbers, peas, runner beans and zucchini only need a small garden footprint and can be trained up a trellis or arbour.

To increase the beauty and productivity of your new garden, consider adding flowers to the plan. Flowers such as marigolds and nasturtium will help attract beneficial insects and potentially eliminate pests at the same time. Some flowers are edible and colourful additions to salads. Even if vegetables are not on your garden menu, a raised bed can be a productive cut flower garden to grow fresh bouquets for your home.

To get a jump start on spring, or to extend the growing season into the autumn, raised bed gardens can be fitted with hoops and plastic to create low tunnels for cool crops including lettuce, radish, kale and carrots.

Ready to assemble raised bed kits are available from local vendors, or you can come up with your own design — the choice is yours.

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